diff --git a/composer.json b/composer.json
index 6130b5c..c2d4f30 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
         "ext-dom": "*",
 
         "simplesamlphp/assert": "~2.0",
-        "simplesamlphp/xml-common": "~2.0"
+        "simplesamlphp/xml-common": "dev-feature/dom-migration-php84"
     },
     "require-dev": {
         "simplesamlphp/simplesamlphp-test-framework": "~1.11"
@@ -31,7 +31,7 @@
     },
     "extra": {
         "branch-alias": {
-            "dev-master": "v2.0.x-dev"
+            "dev-master": "v3.0.x-dev"
         }
     },
     "config": {
diff --git a/src/CAS/Utils/XPath.php b/src/CAS/Utils/XPath.php
index c766c90..d6a5386 100644
--- a/src/CAS/Utils/XPath.php
+++ b/src/CAS/Utils/XPath.php
@@ -4,8 +4,7 @@
 
 namespace SimpleSAML\CAS\Utils;
 
-use DOMNode;
-use DOMXPath;
+use Dom;
 use SimpleSAML\CAS\Constants as C;
 
 /**
@@ -16,21 +15,21 @@
 class XPath extends \SimpleSAML\XPath\XPath
 {
     /**
-     * Get a DOMXPath object that can be used to search for CAS elements.
+     * Get a Dom\XPath object that can be used to search for CAS elements.
      *
-     * @param \DOMNode $node The document to associate to the DOMXPath object.
+     * @param \Dom\Node $node The document to associate to the Dom\XPath object.
      * @param bool $autoregister Whether to auto-register all namespaces used in the document
      *
-     * @return \DOMXPath A DOMXPath object ready to use in the given document, with several
+     * @return \Dom\XPath A Dom\XPath object ready to use in the given document, with several
      *   cas-related namespaces already registered.
      */
-    public static function getXPath(DOMNode $node, bool $autoregister = false): DOMXPath
+    public static function getXPath(Dom\Node $node, bool $autoregister = false): Dom\XPath
     {
         $xp = parent::getXPath($node, $autoregister);
 
         /*
          * - Registering 'cas' to the same URI again is fine.
-         * - If someone previously bound 'cas' to a different URI on the same DOMXPath,
+         * - If someone previously bound 'cas' to a different URI on the same Dom\XPath,
          *   your call will change its meaning for subsequent queries
          * */
         $xp->registerNamespace('cas', C::NS_CAS);
diff --git a/src/CAS/XML/AbstractAttributes.php b/src/CAS/XML/AbstractAttributes.php
index c863240..88f2d83 100644
--- a/src/CAS/XML/AbstractAttributes.php
+++ b/src/CAS/XML/AbstractAttributes.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Constants as C;
 use SimpleSAML\XML\ExtendableElementTrait;
 use SimpleSAML\XMLSchema\XML\Constants\NS;
@@ -80,10 +80,10 @@ public function getIsFromNewLogin(): IsFromNewLogin
     /**
      * Convert this Attributes to XML.
      *
-     * @param \DOMElement|null $parent The element we should append this Attributes to.
-     * @return \DOMElement
+     * @param \Dom\Element|null $parent The element we should append this Attributes to.
+     * @return \Dom\Element
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/CAS/XML/AbstractAuthenticationFailure.php b/src/CAS/XML/AbstractAuthenticationFailure.php
index 4fc400f..d157565 100644
--- a/src/CAS/XML/AbstractAuthenticationFailure.php
+++ b/src/CAS/XML/AbstractAuthenticationFailure.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Type\CodeValue;
 use SimpleSAML\XML\TypedTextContentTrait;
 use SimpleSAML\XMLSchema\Type\StringValue;
@@ -52,10 +52,10 @@ public function getCode(): CodeValue
     /**
      * Convert this AuthenticationFailure to XML.
      *
-     * @param \DOMElement|null $parent The element we should append to.
-     * @return \DOMElement This AuthenticatioFailure-element.
+     * @param \Dom\Element|null $parent The element we should append to.
+     * @return \Dom\Element This AuthenticatioFailure-element.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/CAS/XML/AbstractAuthenticationSuccess.php b/src/CAS/XML/AbstractAuthenticationSuccess.php
index 07e6e48..3ce3a02 100644
--- a/src/CAS/XML/AbstractAuthenticationSuccess.php
+++ b/src/CAS/XML/AbstractAuthenticationSuccess.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 
 /**
  * Class for CAS authenticationSuccess
@@ -72,10 +72,10 @@ public function getProxies(): ?Proxies
     /**
      * Convert this AuthenticationSuccess to XML.
      *
-     * @param \DOMElement|null $parent The element we should append this AuthenticationSuccess to.
-     * @return \DOMElement
+     * @param \Dom\Element|null $parent The element we should append this AuthenticationSuccess to.
+     * @return \Dom\Element
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/CAS/XML/AbstractProxies.php b/src/CAS/XML/AbstractProxies.php
index 17ea9ce..137ba08 100644
--- a/src/CAS/XML/AbstractProxies.php
+++ b/src/CAS/XML/AbstractProxies.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\CAS\Constants as C;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
@@ -45,10 +45,10 @@ public function getProxy(): array
     /**
      * Convert this Proxies to XML.
      *
-     * @param \DOMElement|null $parent The element we should append this Proxies to.
-     * @return \DOMElement
+     * @param \Dom\Element|null $parent The element we should append this Proxies to.
+     * @return \Dom\Element
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/CAS/XML/AbstractProxyFailure.php b/src/CAS/XML/AbstractProxyFailure.php
index 3de8024..9fd7d71 100644
--- a/src/CAS/XML/AbstractProxyFailure.php
+++ b/src/CAS/XML/AbstractProxyFailure.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Type\CodeValue;
 use SimpleSAML\XML\TypedTextContentTrait;
 use SimpleSAML\XMLSchema\Type\StringValue;
@@ -52,10 +52,10 @@ public function getCode(): CodeValue
     /**
      * Convert this ProxyFailure to XML.
      *
-     * @param \DOMElement|null $parent The element we should append to.
-     * @return \DOMElement This ProxyFailure-element.
+     * @param \Dom\Element|null $parent The element we should append to.
+     * @return \Dom\Element This ProxyFailure-element.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/CAS/XML/AbstractProxySuccess.php b/src/CAS/XML/AbstractProxySuccess.php
index 57de651..7d3db67 100644
--- a/src/CAS/XML/AbstractProxySuccess.php
+++ b/src/CAS/XML/AbstractProxySuccess.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 
 /**
  * Class for CAS proxySuccess
@@ -39,10 +39,10 @@ public function getProxyTicket(): ProxyTicket
     /**
      * Convert this ProxySuccess to XML.
      *
-     * @param \DOMElement|null $parent The element we should append to.
-     * @return \DOMElement This ProxySuccess-element.
+     * @param \Dom\Element|null $parent The element we should append to.
+     * @return \Dom\Element This ProxySuccess-element.
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/CAS/XML/AbstractServiceResponse.php b/src/CAS/XML/AbstractServiceResponse.php
index b85e96e..49ec40a 100644
--- a/src/CAS/XML/AbstractServiceResponse.php
+++ b/src/CAS/XML/AbstractServiceResponse.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 
 /**
  * Class for CAS serviceResponse
@@ -39,10 +39,10 @@ public function getResponse(): AbstractResponse
     /**
      * Convert this ServiceResponse to XML.
      *
-     * @param \DOMElement|null $parent The element we should append this ServiceResponse to.
-     * @return \DOMElement
+     * @param \Dom\Element|null $parent The element we should append this ServiceResponse to.
+     * @return \Dom\Element
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
 
diff --git a/src/CAS/XML/Attributes.php b/src/CAS/XML/Attributes.php
index 28b95fa..980f59f 100644
--- a/src/CAS/XML/Attributes.php
+++ b/src/CAS/XML/Attributes.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
@@ -19,7 +19,7 @@ final class Attributes extends AbstractAttributes
     /**
      * Convert XML into a cas:attributes-element
      *
-     * @param \DOMElement $xml The XML element we should load
+     * @param \Dom\Element $xml The XML element we should load
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
@@ -27,7 +27,7 @@ final class Attributes extends AbstractAttributes
      * @throws \SimpleSAML\XMLSchema\Exception\MissingAttributeException
      *   if the supplied element is missing one of the mandatory attributes
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
diff --git a/src/CAS/XML/AuthenticationDate.php b/src/CAS/XML/AuthenticationDate.php
index b2e2e3c..28ef0d9 100644
--- a/src/CAS/XML/AuthenticationDate.php
+++ b/src/CAS/XML/AuthenticationDate.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Type\DateTimeValue;
@@ -44,9 +44,9 @@ public function getTimestamp(): DateTimeValue
     /**
      * Convert this element into an XML document.
      *
-     * @return \DOMElement The root element of the DOM tree
+     * @return \Dom\Element The root element of the DOM tree
      */
-    public function toXML(?DOMElement $parent = null): DOMElement
+    public function toXML(?Dom\Element $parent = null): Dom\Element
     {
         $e = $this->instantiateParentElement($parent);
         $e->textContent = strval($this->getTimestamp());
@@ -58,17 +58,17 @@ public function toXML(?DOMElement $parent = null): DOMElement
     /**
      * Convert XML into a cas:authenticationDate
      *
-     * @param \DOMElement $xml The XML element we should load
+     * @param \Dom\Element $xml The XML element we should load
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
      *   If the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
 
-        return new static(DateTimeValue::fromString($xml->textContent));
+        return new static(DateTimeValue::fromString((string) $xml->textContent));
     }
 }
diff --git a/src/CAS/XML/AuthenticationFailure.php b/src/CAS/XML/AuthenticationFailure.php
index 6492dd2..e703ef9 100644
--- a/src/CAS/XML/AuthenticationFailure.php
+++ b/src/CAS/XML/AuthenticationFailure.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\CAS\Type\CodeValue;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -20,7 +20,7 @@ final class AuthenticationFailure extends AbstractAuthenticationFailure
     /**
      * Initialize an AuthenticationFailure element.
      *
-     * @param \DOMElement $xml The XML element we should load.
+     * @param \Dom\Element $xml The XML element we should load.
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
@@ -28,13 +28,13 @@ final class AuthenticationFailure extends AbstractAuthenticationFailure
      * @throws \SimpleSAML\XMLSchema\Exception\MissingAttributeException
      *   if the supplied element is missing any of the mandatory attributes
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
 
         return new static(
-            StringValue::fromString($xml->textContent),
+            StringValue::fromString((string) $xml->textContent),
             self::getAttribute($xml, 'code', CodeValue::class),
         );
     }
diff --git a/src/CAS/XML/AuthenticationSuccess.php b/src/CAS/XML/AuthenticationSuccess.php
index 7816041..6f0faea 100644
--- a/src/CAS/XML/AuthenticationSuccess.php
+++ b/src/CAS/XML/AuthenticationSuccess.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
@@ -21,7 +21,7 @@ final class AuthenticationSuccess extends AbstractAuthenticationSuccess
     /**
      * Convert XML into a cas:authenticationSuccess-element
      *
-     * @param \DOMElement $xml The XML element we should load
+     * @param \Dom\Element $xml The XML element we should load
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
@@ -29,7 +29,7 @@ final class AuthenticationSuccess extends AbstractAuthenticationSuccess
      * @throws \SimpleSAML\XMLSchema\Exception\MissingAttributeException
      *   if the supplied element is missing one of the mandatory attributes
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
diff --git a/src/CAS/XML/Proxies.php b/src/CAS/XML/Proxies.php
index c3a0e53..d10588f 100644
--- a/src/CAS/XML/Proxies.php
+++ b/src/CAS/XML/Proxies.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 
@@ -18,13 +18,13 @@ final class Proxies extends AbstractProxies
     /**
      * Convert XML into a Proxies-element
      *
-     * @param \DOMElement $xml The XML element we should load
+     * @param \Dom\Element $xml The XML element we should load
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
      *  if the qualified name of the supplied element is wrong
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
diff --git a/src/CAS/XML/ProxyFailure.php b/src/CAS/XML/ProxyFailure.php
index a9a50e1..6ad35d9 100644
--- a/src/CAS/XML/ProxyFailure.php
+++ b/src/CAS/XML/ProxyFailure.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\CAS\Type\CodeValue;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
@@ -20,7 +20,7 @@ final class ProxyFailure extends AbstractProxyFailure
     /**
      * Initialize an ProxyFailure element.
      *
-     * @param \DOMElement $xml The XML element we should load.
+     * @param \Dom\Element $xml The XML element we should load.
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
@@ -28,13 +28,13 @@ final class ProxyFailure extends AbstractProxyFailure
      * @throws \SimpleSAML\XMLSchema\Exception\MissingAttributeException
      *   if the supplied element is missing any of the mandatory attributes
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
 
         return new static(
-            StringValue::fromString($xml->textContent),
+            StringValue::fromString((string) $xml->textContent),
             self::getAttribute($xml, 'code', CodeValue::class),
         );
     }
diff --git a/src/CAS/XML/ProxySuccess.php b/src/CAS/XML/ProxySuccess.php
index 41f2c29..f1e8a32 100644
--- a/src/CAS/XML/ProxySuccess.php
+++ b/src/CAS/XML/ProxySuccess.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
 use SimpleSAML\XMLSchema\Exception\MissingElementException;
@@ -19,7 +19,7 @@ final class ProxySuccess extends AbstractProxySuccess
     /**
      * Initialize an ProxySuccess element.
      *
-     * @param \DOMElement $xml The XML element we should load.
+     * @param \Dom\Element $xml The XML element we should load.
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
@@ -27,7 +27,7 @@ final class ProxySuccess extends AbstractProxySuccess
      * @throws \SimpleSAML\XMLSchema\Exception\MissingAttributeException
      *   if the supplied element is missing any of the mandatory attributes
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
diff --git a/src/CAS/XML/ServiceResponse.php b/src/CAS/XML/ServiceResponse.php
index e16a562..0b9956b 100644
--- a/src/CAS/XML/ServiceResponse.php
+++ b/src/CAS/XML/ServiceResponse.php
@@ -4,7 +4,7 @@
 
 namespace SimpleSAML\CAS\XML;
 
-use DOMElement;
+use Dom;
 use SimpleSAML\CAS\Assert\Assert;
 use SimpleSAML\XML\SchemaValidatableElementInterface;
 use SimpleSAML\XML\SchemaValidatableElementTrait;
@@ -27,7 +27,7 @@ final class ServiceResponse extends AbstractServiceResponse implements SchemaVal
     /**
      * Convert XML into a cas:serviceResponse-element
      *
-     * @param \DOMElement $xml The XML element we should load
+     * @param \Dom\Element $xml The XML element we should load
      * @return static
      *
      * @throws \SimpleSAML\XMLSchema\Exception\InvalidDOMElementException
@@ -35,7 +35,7 @@ final class ServiceResponse extends AbstractServiceResponse implements SchemaVal
      * @throws \SimpleSAML\XMLSchema\Exception\MissingAttributeException
      *   if the supplied element is missing one of the mandatory attributes
      */
-    public static function fromXML(DOMElement $xml): static
+    public static function fromXML(Dom\Element $xml): static
     {
         Assert::same($xml->localName, static::getLocalName(), InvalidDOMElementException::class);
         Assert::same($xml->namespaceURI, static::getNamespaceURI(), InvalidDOMElementException::class);
diff --git a/tests/CAS/XML/AttributesTest.php b/tests/CAS/XML/AttributesTest.php
index 5522238..795c244 100644
--- a/tests/CAS/XML/AttributesTest.php
+++ b/tests/CAS/XML/AttributesTest.php
@@ -65,7 +65,7 @@ public function testMarshalling(): void
             '<cas:myAttribute xmlns:cas="http://www.yale.edu/tp/cas">myValue</cas:myAttribute>',
         );
 
-        /** @var \DOMElement $elt */
+        /** @var \Dom\Element $elt */
         $elt = $document->documentElement;
         $myAttribute = new Chunk($elt);
 
@@ -73,7 +73,7 @@ public function testMarshalling(): void
             '<ssp:myOtherAttribute xmlns:ssp="urn:x-simplesamlphp:namespace">myOtherValue</ssp:myOtherAttribute>',
         );
 
-        /** @var \DOMElement $elt */
+        /** @var \Dom\Element $elt */
         $elt = $document->documentElement;
         $myOtherAttribute = new Chunk($elt);
 
@@ -84,10 +84,11 @@ public function testMarshalling(): void
             [$myAttribute, $myOtherAttribute],
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($attributes),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($attributes);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
@@ -100,7 +101,7 @@ public function testMarshallingElementOrdering(): void
             '<cas:myAttribute xmlns:cas="http://www.yale.edu/tp/cas">myValue</cas:myAttribute>',
         );
 
-        /** @var \DOMElement $elt */
+        /** @var \Dom\Element $elt */
         $elt = $document->documentElement;
         $myAttribute = new Chunk($elt);
         $attributes = new Attributes($authenticationDate, $longTerm, $isFromNewLogin, [$myAttribute]);
@@ -113,7 +114,7 @@ public function testMarshallingElementOrdering(): void
         $this->assertCount(1, $attributesElements);
 
         // Test ordering of cas:attributes contents
-        /** @var \DOMElement[] $attributesElements */
+        /** @var \Dom\Element[] $attributesElements */
         $attributesElements = XPath::xpQuery(
             $attributesElement,
             './cas:authenticationDate/following-sibling::*',
diff --git a/tests/CAS/XML/AuthenticationDateTest.php b/tests/CAS/XML/AuthenticationDateTest.php
index 481edc6..236a95e 100644
--- a/tests/CAS/XML/AuthenticationDateTest.php
+++ b/tests/CAS/XML/AuthenticationDateTest.php
@@ -51,9 +51,10 @@ public function testMarshalling(): void
     {
         $authenticationDate = new AuthenticationDate(self::$authenticationDate);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($authenticationDate),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($authenticationDate);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/AuthenticationFailureTest.php b/tests/CAS/XML/AuthenticationFailureTest.php
index fb56061..bfbd5a8 100644
--- a/tests/CAS/XML/AuthenticationFailureTest.php
+++ b/tests/CAS/XML/AuthenticationFailureTest.php
@@ -54,9 +54,10 @@ public function testMarshalling(): void
             CodeValue::fromEnum(ErrorEnum::INVALID_TICKET),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($authenticationFailure),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($authenticationFailure);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/AuthenticationSuccessTest.php b/tests/CAS/XML/AuthenticationSuccessTest.php
index f189201..452b4d5 100644
--- a/tests/CAS/XML/AuthenticationSuccessTest.php
+++ b/tests/CAS/XML/AuthenticationSuccessTest.php
@@ -64,20 +64,20 @@ public static function setUpBeforeClass(): void
      */
     public function testMarshalling(): void
     {
-        /** @var \DOMElement $firstNameElt */
+        /** @var \Dom\Element $firstNameElt */
         $firstNameElt = DOMDocumentFactory::fromString(
             '<cas:firstname xmlns:cas="http://www.yale.edu/tp/cas">John</cas:firstname>',
         )->documentElement;
 
         $firstName = new Chunk($firstNameElt);
 
-        /** @var \DOMElement $lastNameElt */
+        /** @var \Dom\Element $lastNameElt */
         $lastNameElt = DOMDocumentFactory::fromString(
             '<cas:lastname xmlns:cas="http://www.yale.edu/tp/cas">Doe</cas:lastname>',
         )->documentElement;
         $lastName = new Chunk($lastNameElt);
 
-        /** @var \DOMElement $emailElt */
+        /** @var \Dom\Element $emailElt */
         $emailElt = DOMDocumentFactory::fromString(
             '<cas:email xmlns:cas="http://www.yale.edu/tp/cas">jdoe@example.org</cas:email>',
         )->documentElement;
@@ -97,29 +97,30 @@ public function testMarshalling(): void
 
         $authenticationSuccess = new AuthenticationSuccess($user, $attributes, $proxyGrantingTicket, $proxies);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($authenticationSuccess),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($authenticationSuccess);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 
 
     public function testMarshallingElementOrdering(): void
     {
-        /** @var \DOMElement $firstNameElt */
+        /** @var \Dom\Element $firstNameElt */
         $firstNameElt = DOMDocumentFactory::fromString(
             '<cas:firstname xmlns:cas="http://www.yale.edu/tp/cas">John</cas:firstname>',
         )->documentElement;
 
         $firstName = new Chunk($firstNameElt);
 
-        /** @var \DOMElement $lastNameElt */
+        /** @var \Dom\Element $lastNameElt */
         $lastNameElt = DOMDocumentFactory::fromString(
             '<cas:lastname xmlns:cas="http://www.yale.edu/tp/cas">Doe</cas:lastname>',
         )->documentElement;
         $lastName = new Chunk($lastNameElt);
 
-        /** @var \DOMElement $emailElt */
+        /** @var \Dom\Element $emailElt */
         $emailElt = DOMDocumentFactory::fromString(
             '<cas:email xmlns:cas="http://www.yale.edu/tp/cas">jdoe@example.org</cas:email>',
         )->documentElement;
@@ -146,7 +147,7 @@ public function testMarshallingElementOrdering(): void
         $this->assertCount(1, $authenticationSuccessElements);
 
         // Test ordering of cas:authenticationSuccess contents
-        /** @var \DOMElement[] $authenticationSuccessElements */
+        /** @var \Dom\Element[] $authenticationSuccessElements */
         $authenticationSuccessElements = XPath::xpQuery(
             $authenticationSuccessElement,
             './cas:user/following-sibling::*',
diff --git a/tests/CAS/XML/IsFromNewLoginTest.php b/tests/CAS/XML/IsFromNewLoginTest.php
index 829fa66..e27f83a 100644
--- a/tests/CAS/XML/IsFromNewLoginTest.php
+++ b/tests/CAS/XML/IsFromNewLoginTest.php
@@ -44,9 +44,10 @@ public function testMarshalling(): void
     {
         $isFromNewLogin = IsFromNewLogin::fromString('true');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($isFromNewLogin),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($isFromNewLogin);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/LongTermAuthenticationRequestTokenUsedTest.php b/tests/CAS/XML/LongTermAuthenticationRequestTokenUsedTest.php
index d74d427..f60c0b3 100644
--- a/tests/CAS/XML/LongTermAuthenticationRequestTokenUsedTest.php
+++ b/tests/CAS/XML/LongTermAuthenticationRequestTokenUsedTest.php
@@ -44,9 +44,10 @@ public function testMarshalling(): void
     {
         $longTerm = LongTermAuthenticationRequestTokenUsed::fromString('true');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($longTerm),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($longTerm);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/ProxiesTest.php b/tests/CAS/XML/ProxiesTest.php
index 48110db..bbbd81f 100644
--- a/tests/CAS/XML/ProxiesTest.php
+++ b/tests/CAS/XML/ProxiesTest.php
@@ -49,9 +49,10 @@ public function testMarshalling(): void
         $entry2 = Proxy::fromString('https://example.org/proxy/2');
         $list = new Proxies([$entry1, $entry2]);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($list),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($list);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/ProxyFailureTest.php b/tests/CAS/XML/ProxyFailureTest.php
index 6184bf6..841395c 100644
--- a/tests/CAS/XML/ProxyFailureTest.php
+++ b/tests/CAS/XML/ProxyFailureTest.php
@@ -54,9 +54,10 @@ public function testMarshalling(): void
             CodeValue::fromEnum(ErrorEnum::INVALID_REQUEST),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($proxyFailure),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($proxyFailure);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/ProxyGrantingTicketTest.php b/tests/CAS/XML/ProxyGrantingTicketTest.php
index f39c5b0..99dda93 100644
--- a/tests/CAS/XML/ProxyGrantingTicketTest.php
+++ b/tests/CAS/XML/ProxyGrantingTicketTest.php
@@ -44,9 +44,10 @@ public function testMarshalling(): void
     {
         $proxyGrantingTicket = ProxyGrantingTicket::fromString('PGTIOU-84678-8a9d...');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($proxyGrantingTicket),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($proxyGrantingTicket);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/ProxySuccessTest.php b/tests/CAS/XML/ProxySuccessTest.php
index 33e12a5..a23ca6d 100644
--- a/tests/CAS/XML/ProxySuccessTest.php
+++ b/tests/CAS/XML/ProxySuccessTest.php
@@ -51,9 +51,10 @@ public function testMarshalling(): void
             ProxyTicket::fromString('PT-1856392-b98xZrQN4p90ASrw96c8'),
         );
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($proxySuccess),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($proxySuccess);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/ProxyTest.php b/tests/CAS/XML/ProxyTest.php
index c7826b8..4d5b052 100644
--- a/tests/CAS/XML/ProxyTest.php
+++ b/tests/CAS/XML/ProxyTest.php
@@ -44,9 +44,10 @@ public function testMarshalling(): void
     {
         $proxy = Proxy::fromString('https://example.org/proxy');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($proxy),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($proxy);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/ProxyTicketTest.php b/tests/CAS/XML/ProxyTicketTest.php
index f3c973b..f9935e7 100644
--- a/tests/CAS/XML/ProxyTicketTest.php
+++ b/tests/CAS/XML/ProxyTicketTest.php
@@ -44,9 +44,10 @@ public function testMarshalling(): void
     {
         $proxyTicket = ProxyTicket::fromString('PT-1856392-b98xZrQN4p90ASrw96c8');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($proxyTicket),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($proxyTicket);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/ServiceResponseTest.php b/tests/CAS/XML/ServiceResponseTest.php
index ab65378..d96d38c 100644
--- a/tests/CAS/XML/ServiceResponseTest.php
+++ b/tests/CAS/XML/ServiceResponseTest.php
@@ -71,7 +71,7 @@ public function testMarshalling(): void
         $longTerm = LongTermAuthenticationRequestTokenUsed::fromString('true');
         $isFromNewLogin = IsFromNewLogin::fromString('true');
 
-        /** @var \DOMElement $element */
+        /** @var \Dom\Element $element */
         $element = DOMDocumentFactory::fromString(
             '<cas:myAttribute xmlns:cas="http://www.yale.edu/tp/cas">myValue</cas:myAttribute>',
         )->documentElement;
@@ -84,9 +84,10 @@ public function testMarshalling(): void
         );
         $serviceResponse = new ServiceResponse($authenticationSuccess);
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($serviceResponse),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($serviceResponse);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }
diff --git a/tests/CAS/XML/UserTest.php b/tests/CAS/XML/UserTest.php
index a72dd81..2891f23 100644
--- a/tests/CAS/XML/UserTest.php
+++ b/tests/CAS/XML/UserTest.php
@@ -44,9 +44,10 @@ public function testMarshalling(): void
     {
         $user = User::fromString('username');
 
-        $this->assertEquals(
-            self::$xmlRepresentation->saveXML(self::$xmlRepresentation->documentElement),
-            strval($user),
-        );
+        $expectedXml = self::$xmlRepresentation->saveXml(self::$xmlRepresentation->documentElement);
+        $this->assertNotFalse($expectedXml);
+        $actualXml = strval($user);
+
+        $this->assertXmlStringEqualsXmlString($expectedXml, $actualXml);
     }
 }